Loratadine is a long acting, non-sedating antihistamine with no significant sedative or anti-muscarinic activity. Loratadine is virtually completely water insoluble under neutral pH. Loratadine solutions having a pH of between 2.5 to 3.1 are disclosed in U.S. Pat. No. 6,132,758. A major disadvantage of loratadine in an aqueous solution is the oxidative degradation of the compound into inactive metabolites. U.S. Pat. No. 6,132,758 describes stable loratadine syrups that include aminopolycarboxylic acids and salts thereof as antioxidants to prevent the oxidative degradation.
Syrups, elixirs, solutions, and suspensions are traditional dosage forms for oral medication. These liquid formulations are typically measured by pouring into a spoon, but this approach has the great drawback of spillage. The risk of spillage can cause people to underfill or spill from the spoon, leading to inaccurate dosage. With elderly people, children, and the infirm, lack of motor skills or poor attention can cause difficulty in filling a spoon with a liquid and bringing it to the mouth and can be a serious impediment to administering the medicine. Solid formulations such as pills, tablets, and capsules are also difficult for children and for elderly, infirm people to swallow Recently, spill resistant pharmaceutical preparations for the oral delivery of pharmaceutically active agents have been described in the commonly owned U.S. Pat. Nos. 5,881,926, 6,071,523, 6,102,254, 6,355,258, and 6,399,079, herein incorporated by reference. These patents describe oral dosage forms for the delivery of active agents that do not spill easily, are organoleptically pleasing and are storage stable.
Surprisingly, we have found that loratadine in a spill resistant pharmaceutical suspension is resistant to oxidative degradation and has increased rheological storage stability as compared to solutions of loratadine.